Facebook is a social networking website that allows users to create profiles, connect with friends and family, share photos and updates. It was founded in 2004 by Mark Zuckerberg and initially launched for Harvard students. The site has since expanded globally and now has over 200 million users. Facebook's mission is to make the world more open and connected by giving people the power to share. While social networking allows users to stay connected with others and share interests, it also raises privacy and safety concerns that require users to be cautious about sharing personal information publicly.